A diet high in fruits, vegetables, whole grains, beans, nuts, and fish lowers the risk of developing Parkinson’s disease (PD). A compilation of data from the Health Professionals’ Follow-up Study of 49,692 men and the Nurses’ Health Study of 81,676 women showed that these dietary choices could lower the risk of PD by 30 percent, compared to a typical Western diet. (Gao X, et al., Prospective study of dietary pattern and risk of Parkinson disease. Am J Clin Nutr. 2007 Nov;86(5):1486-94.)
The typical Western diet that they reported was high in saturated fat, refined grains, red meat, sweets, and fried foods. Most people realize that these foods are unhealthy, but this has not stopped their widespread consumption. The authors noted the great benefit of a plant-based diet plus fish in preventing PD, and this is the same diet that appears to protect from other degenerative diseases.
Eating fruits, vegetables, and fish have further benefits for the brain. It appears that a high consumption of these foods reduces the risk of dementia by 28 to 40 percent, depending on the kind of dementia. In this French study, 8085 men and women over 65 years old were followed for four years. Omega-3 oils from fish, flaxseeds, walnuts, and canola oil reduced the risks of dementia. On the other hand, a diet high omega-6 fats from meats, eggs, and commercially processed vegetable oils increased the risk. (Barberger-Gateau P, et al., Dietary patterns and risk of dementia: the Three-City cohort study. Neurology 2007 Nov 13;69(20):1921-30.)
In fact, people who consumed lots of omega-6 fats from these sources without adequate consumption of omega-3 fats had twice the risk of developing dementia from all causes, including Alzheimer’s disease.
Vitamin D seems to be very popular in research circles these days, with many articles on a variety of topics. A new report suggests that high blood levels of vitamin D (mainly from sun exposure, fish consumption, and dietary supplements) might help ward off type 2 diabetes. (Mattila C, et al., Serum 25-hydroxyvitamin D concentration and subsequent risk of type 2 diabetes. Diabetes Care 2007 Oct;30(10):2569-70.)
Researchers evaluated 4,097 men and women from 40 to 69 years old who did not have diabetes at the start of the study. Over 17 years, those subjects with the highest blood levels of vitamin D were 40 percent less likely to develop diabetes than those with the lowest levels. I have previously reported that most people do not get adequate vitamin D from either the sun or diet, so supplements are often essential to maintain the highest blood levels. Typical daily recommendations are for supplements of 1000 to 2000 IU of natural vitamin D (vitamin D3, or cholecalciferol). Most milk is fortified with synthetic vitamin D (D2), although some (but not all) organic milk has the natural form, so you have to look carefully.
This research is a confirmation of earlier data from the Nurses’ Health Study. That research on 83,779 subjects showed that vitamin D from supplements reduced diabetes risk by 13 percent. When vitamin D was combined with increased calcium intake, the risk was reduced by 33 percent. (Pittas AG, et al., Vitamin D and calcium intake in relation to type 2 diabetes in women. Diabetes Care 2006 Mar;29(3):650-6.)
Low blood levels of markers for vitamin B12 function are associated with an increased rate of mental decline. A study in England evaluated 1648 participants over 65 years old for 10 years. Serum markers for B12 activity (holotranscobalamin and methylmalonic acid) were inversely associated with mental decline, while the level of B12 itself was not related to mental function, indicating that the B12 level is not as important as its activity. (Clarke R, et al., Low vitamin B-12 status and risk of cognitive decline in older adults. Am J Clin Nutr 2007 Nov;86(5):1384-91.)
The highest level of the markers was associated with a 30 percent reduction in loss of cognitive function over the 10 years. On the other hand, higher levels of homocysteine (a metabolite linked to loss of brain function and heart disease) were associated with a greater than 50 percent increase in the rate of cognitive decline.
Vitamin B12 helps to lower levels of homocysteine, but this is not the only way it might help brain function. In another study with some of the same researchers, 195 subjects were given supplements of B12, folate, or a placebo for six months. B12 and folate supplements increased the level of betaine in the blood. Betaine is a methyl donor, and higher levels were associated with improved memory. (Eussen SJ, et al., The association of betaine, homocysteine and related metabolites with cognitive function in Dutch elderly people. Br J Nutr. 2007 Nov;98(5):960-8.)
Maintaining both a trim waist and upper body strength is one way to reduce the risk of dying early. In a study of 4107 men 60 to 79 years old, those with the largest biceps with waists less than 40 inches had the lowest mortality over a six-year period. (Wannamethee SG, et al., Decreased muscle mass and increased central adiposity are independently related to mortality in older men. Am J Clin Nutr. 2007 Nov;86(5):1339-46.)
Neither waist size nor bicep size alone were as predictive, although bicep size did relate to lowered mortality. This indicates that it is most important to stay trim and maintain strength at the same time. Waist size greater than 40 inches and a high waist to hip ratio were both associated with an increased risk of mortality. A large bicep combined with a waist size over 40 inches was associated with a 36 percent higher mortality risk.
Even mild exercise helps reduce the incidence of heart disease in diabetic patients. In a Japanese study of 102 diabetics followed for 17 months, the incidence of cardiovascular disease was just 1.6 percent among those who maintained their exercise program of a daily 20-30 minute walk. Among those who dropped out of the program, the incidence of cardiovascular disease (heart attack or stroke) was 18 percent. (Shinji S, et al., Adherence to a home-based exercise program and incidence of cardiovascular disease in type 2 diabetes patients. Int J Sports Med. 2007 Oct;28(10):877-9.)
Although this is a small study, it shows the value of even mild exercise when maintained consistently. Diabetics are particularly prone to cardiovascular disease, so mild exercise can have a profound protective effect.
In an Australian study of 302 diabetic subjects over 70 years old, a regular, moderate exercise program led to a 74 percent decline in the risk of developing dementia. (Bruce DG, et al., Predictors of cognitive impairment and dementia in older people with diabetes. Diabetologia 2007 Dec 5 [Epub ahead of print])
Bioflavonoids include a large number of plant compounds that have antioxidant, anti-inflammatory, anti-allergic, and anti-cancer properties. Quercetin has been particularly helpful for allergy control. A new report from the Nurses’ Health Study of 66,940 women shows that those with the highest intake of two flavonoids, kaempferol and luteolin (both found in citrus and other sources) had a 40 percent and 34 percent reduction, respectively, in the incidence of ovarian cancer. (Gates MA, et al., A prospective study of dietary flavonoid intake and incidence of epithelial ovarian cancer. Int J Cancer. 2007 Nov 15;121(10):2225-32.)
An earlier study on brain tumor cells (glioblastoma) showed that kaempferol induced apoptosis (death) in the cancer cells. (Sharma V, et al., Kaempferol induces apoptosis in glioblastoma cells through oxidative stress. Mol Cancer Ther 2007 Sep;6(9):2544-53.)
Kaempferol is abundant in berries, such as strawberries and cranberries, but is also present in significant amounts in broccoli, tea, grapefruit, and colored beans (pinto and red beans, for examples). Luteolin is found in turnips, spinach, and hot peppers. It is also present in parsley, artichokes, and basil. All of these flavonoids protect DNA from oxidative damage among their other effects. One key to prevention of degenerative diseases is to eat a wide variety of naturally colorful foods, as they are bound to contain a number of flavonoids and other protective compounds.
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